Part of "X-ray spectroscopic studies of the solid state." Technical report number 1 is "K spectra of potassium chloride" by Lyman G. Parratt and E. Leonard Jossem of Cornell University, Department of Physics. The research that led to this report was supported by the Office of Naval Research and by the United States Air Force through the Office of Scientific Research of the Air Research and Development Command. Topics in this report include: crystals, molecular spectroscopy, absorption, molecular structure, potassium compounds and chlorides.